1. Field of the Invention
The present invention relates to a method of manufacturing a liquid ejection head.
2. Description of the Related Art
In recent years, a liquid ejection head (hereinafter also referred simply to as “head”) is demanded to perform printing in higher image quality. As a method of realizing printing in higher image quality, there are known a method of minimizing the diameter of an ejection orifice of the head, and a method of arranging the ink ejection orifices in higher density. When printing is performed with use of a head having the ejection orifices arranged in higher density, energy is input simultaneously to a larger number of heaters. Therefore, a larger amount of heat is generated in the head, and the generated heat is liable to be stored in the head. The storage of heat in the head may cause change in ejection characteristics such as an ejection amount, and further may influence the high image quality printing in some cases. As a countermeasure, there is known a method of decreasing the flow resistance from the heater to an upper opening of the ejection orifice, to thereby reduce the input energy.
As one example of the method of decreasing the flow resistance from the heater to the upper opening of the ejection orifice, there is known a method described in U.S. Pat. No. 7,585,616. In a head described in U.S. Pat. No. 7,585,616, the ejection orifice provided in a flow path forming member includes an upper ejection orifice and a lower ejection orifice which communicate to each other, and the lower ejection orifice has a tapered shape in which across-sectional area decreases toward the upper ejection orifice.